Thanks, Bob, but I'm not sure my assumption is completely correct. If we ignore those goofy periods that we've seen in other stamped sequences, I think the logical cluster in this one is, "IPC 1708, DG 6296, 100 HP RAF, BE 12" (assuming that " B. F. Iz" might have been hard to read). We know that horsepower numbers were often inaccurate, but usually not by a margin of 50% as this would have been.

Any thoughts? Maybe the OP can get a good photo of the stamped information for us to decipher.